Houseplant Leaf Damage: Pests or Disease?

Hello,
I was wondering if you would know what would cause this type of damage to a leaf on a ZZ plant? I have several other plants with similar damage to their leaves including several calathea, crotons, and pothos. I’m assuming some type of pest, however, the only thing I’ve been able to spot is some fungus knats. Thank you for your time,
Josh